JSoup 不适用于 AsyncTask

我注意到我的应用程序发生了一件有趣的事情（我在 AsyncTask 中使用 Jsoup）

之后我的应用程序崩溃了。 LogCat 是：

 12-15 11:16:43.023: I/dalvikvm(371): Could not find method org.jsoup.Jsoup.connect, referenced from method com.example.myexample.MainActivity$MyTask.doInBackground
12-15 11:16:43.033: W/dalvikvm(371): VFY: unable to resolve static method 3462: Lorg/jsoup/Jsoup;.connect (Ljava/lang/String;)Lorg/jsoup/Connection;
12-15 11:16:43.033: D/dalvikvm(371): VFY: replacing opcode 0x71 at 0x0003
12-15 11:16:43.033: D/dalvikvm(371): VFY: dead code 0x0006-000d in Lcom/example/myexample/MainActivity$MyTask;.doInBackground ([Ljava/lang/String;)Ljava/lang/String;
12-15 11:16:43.113: W/dalvikvm(371): threadid=9: thread exiting with uncaught exception (group=0x40015560)
12-15 11:16:43.133: E/AndroidRuntime(371): FATAL EXCEPTION: AsyncTask #1
12-15 11:16:43.133: E/AndroidRuntime(371): java.lang.RuntimeException: An error occured while executing doInBackground()
12-15 11:16:43.133: E/AndroidRuntime(371):  at android.os.AsyncTask$3.done(AsyncTask.java:200)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.util.concurrent.FutureTask.run(FutureTask.java:138)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
12-15 11:16:43.133: E/AndroidRuntime(371):  at java.lang.Thread.run(Thread.java:1019)

与异步相关的致命异常！但我不明白为什么 我的应用程序：

public class MainActivity extends Activity {
MyTask mt;
  TextView tvInfo;
  String URL="http://en.wikipedia.org/";
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    tvInfo = (TextView) findViewById(R.id.tvInfo);
  }

  public void onclick(View v) {
    mt = new MyTask();
    mt.execute(URL);
  }

  class MyTask extends AsyncTask<String, Void, String> {
      Document doc;
      String title=null;
      String what1=null;
    @Override
    protected void onPreExecute() {
      super.onPreExecute();
      tvInfo.setText("Please wait...");
    }

    protected String doInBackground(String... params) {
      // TimeUnit.SECONDS.sleep(2);
       String url=params[0];
       Document doc;

    try {
        doc = Jsoup.connect(url).get();
        String what1=doc.title();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


      return what1;
    }

    protected void onPostExecute(String result) {
      super.onPostExecute(result);
      tvInfo.setText(result);
    }
  }
}

如果我更改代码（没有 JSoup），异步效果很好：

public class MainActivity extends Activity {
MyTask mt;
  TextView tvInfo;
  String URL="http://en.wikipedia.org/";
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    tvInfo = (TextView) findViewById(R.id.tvInfo);
  }

  public void onclick(View v) {
    mt = new MyTask();
    mt.execute(URL);
  }

  class MyTask extends AsyncTask<String, Void, String> {
      Document doc;
      String title=null;
    @Override
    protected void onPreExecute() {
      super.onPreExecute();
      tvInfo.setText("Please wait");
    }

    protected String doInBackground(String... params) {
      // TimeUnit.SECONDS.sleep(2);
       String url=params[0];
       //doc = Jsoup.connect(url).get();
       //String title = doc.title();
      // Log.d("AsyncTask doInBackground","URL: " + params[0]);
      return url;
    }

    protected void onPostExecute(String result) {
      super.onPostExecute(result);
      tvInfo.setText(result);
    }
  }
}

在 TextView 中我得到了 Wiki 的 URL。 拜托，任何人都可以帮我解决这个问题吗？ 谢谢你！

P.S 我在清单文件中添加了互联网的权限 P.P.S 我使用 JSoup 版本 1.7.1（作为外部 jar 文件添加）

我这样做是右键单击项目 - >构建路径 - >添加外部档案

请撤消该操作，然后创建一个libs/项目中的目录（作为同级src/, res/等）（如果您还没有）。然后，将 JSoup JAR 放入libs/目录。这都会将其添加到您的构建路径中and将其内容包含在您的 APK 文件中。